1. Field of the Invention
The present invention generally relates to an apparatus for processing a call of a wireless LAN using a callback function and a method thereof for processing the call between terminals operated on the basis of the wireless LAN, and more specifically to an apparatus for processing a call of a wireless LAN using a callback function and a method thereof for connecting the call when target terminals are converted into a keep-alive state from a keep-dead state (for example, out of an access point (AP) section or power is turned off) by periodically receiving state information of other terminals in a transmitting terminal.
2. Description of the Related Art
Recently, as a wireless office telephone service using Wireless Office Solution (WOS) has been regularized, Private Branch exchange (PBX) performing a simple in-house exchange function in the past has almost disappeared. The wireless office telephone service securing mobility as receiving all advantages of an Internet Protocol (IP)-based IP PBX has become influential rapidly in the domestic market along with marketing strategies of mobile communication providers.
In another words, a Public Switched Telephone Network (PSTN)-based PBX is changed to an IP-based PBX and combined with Code Division Multiple Access (CDMA) technologies, thus enterprises have concretely accomplished cable and wireless integration in themselves.
Hereinafter, a configuration of a system performing a wireless office telephone service will be more fully described in reference to the accompanying drawings.
FIG. 1 is a format diagram conceptually illustrating an available access range section between a wireless LAN exchange and terminals.
As shown in FIG. 1, a wireless office telephone service is performed by installing an AP 20, a wireless LAN (local area network) base station, in an IP-based PBX, which is a wireless LAN exchange 10.
However, in the above configuration, if terminals (T1˜Tn) are out of an available range of the AP 20 , that is, they are located in the same position as a terminal (Ts), it becomes inaccessible. Thus, though the terminals are not busy, there is no way to connect calls.
In addition, since wireless LAN terminals moving much have a lot of battery consumption capacities, it is easy to use up all power. Therefore, though the terminals are not busy, it is impossible to connect calls owing to power-off states of the terminals.
Accordingly, when target terminals (destination terminals or receiving terminals) re-enter the available range after going out of the available range of the AP 20 or power is turned on by changing a battery from a keep-dead state due to a power-off state, a service for automatically connecting calls to the target terminals themselves is requested.